221311123400 has 24 divisors (see below), whose sum is σ = 514548362370. Its totient is φ = 88524449280.

The previous prime is 221311123399. The next prime is 221311123403. The reversal of 221311123400 is 4321113122.

It can be written as a sum of positive squares in 3 ways, for example, as 211542963844 + 9768159556 = 459938^2 + 98834^2 .

It is a super-2 number, since 2×221311123400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (221311123403) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 553277609 + ... + 553278008.

Almost surely, 2^221311123400 is an apocalyptic number.

221311123400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221311123400 is an abundant number, since it is smaller than the sum of its proper divisors (293237238970).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221311123400 is a wasteful number, since it uses less digits than its factorization.

221311123400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1106555633 (or 1106555624 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 221311123400 its reverse (4321113122), we get a palindrome (225632236522).

The spelling of 221311123400 in words is "two hundred twenty-one billion, three hundred eleven million, one hundred twenty-three thousand, four hundred".